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Co-precipitation synthesis of Nd:YAG nanopowders: the effect of joint thermal and mechanical treatment
|Maria Luisa Saladino 1, Eugenio Caponetti 1, Filomena Serra 2, Stefano Enzo 2|
1. Università di Palermo (UNIPA), Viale delle Scienze, Pallermo 90128, Italy
Nanopowders of Yttrium Aluminium Garnet (YAG) doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium and yttrium nitrate and neodymium oxide with ammonia giving samples of nominal stoichiometry NdX:Y(3-X)Al5O12 (where X = 0, 0.02, 0.05, 0.10, 0.19, 0.38, 0.72). After washing and drying, the hydroxide precursors were heat treated for different times and temperature. Differential Thermal Analysis curves (DTA) from room temperature up to 1000 C show the presence of exothermal events accompanying phase transformation phenomena. X-ray diffraction (XRD) investigations conducted with a high-resolution powder diffractometer on the specimens calcined at high-temperature show that the samples are single phase garnet except for the highest concentration of Nd, where a minor hexagonal YAlO3 phase may also be present. Precise determination of the cubic garnet lattice parameters as a function of the Neodymium content according to the Rietveld method shows a parabolic increase from the value of 12.022 (±2) Å for XNd = 0 up to 12.128 (±2) Å for XNd= 0.72. The line broadening analysis after correction for instrumental factors indicates that the average crystallite size is in the range 50-70 nm. Results will be presented and discussed concerning the role of a mechanical treatment on the amorphous powder in order to skip kinetically the formation of metastable phases and to favor precipitation of the garnet with consistent neodymium content.
Presentation: poster at E-MRS Fall Meeting 2005, Laser Ceramic Symposium, by Maria Luisa Saladino
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-06-03 08:48 Revised: 2009-06-07 00:44